642 Works

Carroll symmetry in gravity and string theory

I will discuss the small speed of light expansion of general relativity, utilizing the modern perspective on non-Lorentzian geometry. The leading order in the expansion leads to an action that corresponds to the electric Carroll limit of general relativity, of which I will highlight some interesting properties. The next-to-leading order will also be obtained, which exhibits a particular subsector that correspond to the magnetic Carroll limit, which features a solution that describes the Carroll limit...

Fundamental physics with 21cm observations


Quasiprobability representations of qubits

Negativity in a quasi-probability representation is typically interpreted as an indication of nonclassical behavior.  However, this does not preclude bases that are non-negative from having interesting applications---the single-qubit stabilizer states have non-negative Wigner functions and yet play a fundamental role in many quantum information tasks. We determine what other sets of quantum states and measurements of a qubit can be non-negative in a quasiprobability representation, and identify nontrivial groups of unitary transformations that permute such...

Entanglement Generation in Relativistic Quantum Fields

We present a general, analytic recipe to compute the entanglement that is generated between arbitrary, discrete modes of bosonic quantum fields by Bogoliubov transformations. Our setup allows the complete characterization of the quantum correlations in all Gaussian field states. Additionally, it holds for all Bogoliubov transformations. These are commonly applied in quantum optics for the description of squeezing operations, relate the modedecompositions of observers in different regions of curved spacetimes, and describe observers moving along...

MUBs and SICs

Abstract: Complete sets of mutually unbiased bases are clearly \'cousins\' of SICs. One difference is that there is a \'theory\' for MUBs, in the sense that they are straightforward to construct in some cases, and probably impossible to construct in others. Moreover complete sets of MUBs do appear naturally in the algebraic geometry of projective space (in particular they come from elliptic curves with certain symmetries). I will describe some unsuccessful attempts I have made...

Geometry and the entanglement spectrum in the fractional quantum Hall effect.

Fractional quantum hall states with nu = p/q  have a characteristic geometry  defined by the electric quadrupole moment of the neutral composite boson that is formed by "flux attachment" of q "flux quanta" (guiding-center orbitals) to p charged particles.    This characterizes the  "Hall viscosity".    For FQHE states described by a conformal field theory with a Euclidean metric  g_ab, the quadrupole moment is proportional to the "guiding-center spin" of the composite boson and the inverse metric.      ...

DAEdALUS and Dark Matter

In the search for dark matter, neutrino experiments can play a key role by doubling as dark matter production and detection experiments. I will describe how the proposed DAEdALUS decay-at-rest neutrino experiment can be used to search for MeV-scale dark matter, with particular emphasis on dark matter produced through a dark photon in rare neutral pion decays. The fact that the dark photon need not be on-shell opens up a wide range of new possibilities...


Quantum cosmology in Lorentz-violating gravity

Lorentz invariance is considered a fundamental symmetry of physical theories. However, while Lorentz violations are strongly constrained in the matter sector, constraints in the gravitational sector are weaker, allowing to contemplate the idea of Lorentz-violating gravity theories. In this talk I will discuss the effects of Lorentz violations in the quantum cosmology scenario by analyzing the properties of a simple anisotropic model in the framework of Horava-Lifshitz gravity and, if time permitting, some partial results...

Welcome and Opening Remarks

Confined contextuality: How specific counterfactual paradoxes in pre- and post-selected Kochen-Specker sets give rise to experimentally observable consequences.

The Kochen-Specker (KS) theorem can gives rise to logical paradoxes under pre- and post-selection in which the contextual behavior is confined to specific observables of a system. Weak measurements allow direct experimental observation of the nonclassical behavior of these specific observables. This presents an experimental advantage over other tests of KS inequalities which rule out a particular class of counterfactual noncontextual hidden variable models, but can never specify where the contradiction occurs, nor make any...

Scale Without Conformal Invariance

We investigate the theoretical implications of scale without conformal invariance in quantum field theory. We argue that the RG flows of such theories correspond to recurrent behaviors, i.e. limit cycles or ergodicity. We discuss the implications for the a-theorem and show how dilatation generators do generate dilatations. Finally, we discuss possible well-behaved non-conformal scale-invariant examples.

Quantum theory and spacetime: a different perspective

Quantum information theory has taught us that quantum theory is just one possible probabilistic theory among many others. In the talk, I will argue that this "bird's-eye" perspective does not only allow us to derive the quantum formalism from simple physical principles, but also reveals surprising connections between the structures of spacetime and probability which can be phrased as mathematical theorems about information-theoretic scenarios.

Searching for the Dark Universe

For nearly a century, we have known that the majority of matter in the universe is not luminous. In the past few decades we have come to be certain that this matter is not only not luminous but not made out of any of the particle ever observed in a laboratory. I will describe the ongoing hunt for this matter and the prospects for the discovery in the next decade. I will further discuss recent...

Introduction to Anomalies in Quantum Field Theory

Introduction to Symmetries in Quantum Field Theory

Analog Duality

I will discuss a new duality between strongly coupled and weakly coupled condensed matter systems. It can be obtained by combining the gauge-gravity duality with analog gravity. In my talk I will explain how one arrives at the new duality, what it can be good for, and what questions this finding raises.

Superluminalities in Galileon theories

Practical quantum-key-distribution systems with detector efficiency mismatch: attacks and secret key rates

Imperfections in devices are inevitable in practice.  In this talk, we focus on the imperfection of QKD systems in the detectors, namely that the efficiencies of the detectors are not completely identical.  We show some practical attacks that specifically exploit this efficiency mismatch and demonstrate how Eve may obtain some information on the final key if Alice and Bob are unaware of the attack.  Also, we discuss the upper and lower bounds on the secret...

Coordinate Charts on Character Varieties via Non-abelianization

Classical work by Thurston in the theory of surfaces gives symplectic co-ordinate charts on Teichm├╝ller space, associated to quadratic differentials. Motivated by wall crossing in 4d field theories Gaiotto, Moore and Neitzke defined a generalization of these; giving maps from the moduli of one dimensional local systems on a spectral curve to the moduli space of n-dimensional local systems on a non-compact Riemann surface. I will...

Effective actions for gravity

Towards a generally covariant cutoff using sampling theory

Discontinuous Galerkin methods for general relativistic hydrodynamics

I will present the formalism needed for the application of discontinuous Galerkin methods to general relativistic hydrodynamics and the results obtained in the spherically symmetric case.

Partially Massless Gravity

On de Sitter space, there exists a special value for the mass of a graviton for which the linear theory propagates 4 rather than 5 degrees of freedom. If a fully non-linear version of the theory exists and can be coupled to known matter, it would have interesting properties and could solve the cosmological constant problem. I will describe evidence for and obstructions to the existence of such a theory.

Registration Year

  • 2022

Resource Types

  • Audiovisual


  • Perimeter Institute